lunes, 18 de noviembre de 2013

State Lab
Finds a Positive Sample, no human cases identified yet.

A
Washington state company is recalling sliced apples due to the potential for
Listeria contamination. The contamination was discovered by testing conducted
by Minnesota Health Department. A sample tested was found to be positive for Listeria monocytogenes.

There have
been no know Listeria outbreaks
associated with sliced apples, however these product had been recalled
in the 2012. Perhaps this is why MN Dept. of Health decided to pull this
sample…perhaps it was just somebody pulling samples. Was the level of
contamination significant? Studies have shown that Listeria can survive on apples and that it has grown on sliced
apples when that product was temperature abused.

How risk is
evaluated for a given product is rarely constant. This was the case with
cantaloupes, where Listeria was
probably not on the radar of those conducting a risk analysis, until the Jensen
related outbreak in 2011. And so now for companies packing fresh apple slice,
they too will need to include Listeria
as part of their hazard analysis, and with this, they will need to implement
environmental control measures in the processing environment.

The company
sold the recalled product to retail customers and because, in some cases, the
recalled product was shipped to regional distribution centers, Crunch Pak is taking
the extra precautionary measure of issuing this recall nationwide to assure
that consumers who may have purchased the product are properly alerted.

martes, 12 de noviembre de 2013

The first
reported multistate outbreak from undercooked chicken liver in the US

Six people
were sickened and two were hospitalized, said the Morbidity and Mortality
Weekly Report (MMWR) at the Centers for Disease Control and Prevention (CDC).Affected were exposed to raw or lightly cooked chicken
livers produced at the same poultry factory (establishment A) collected livers yielded
the same strain of C. jejuni.

In October
2012 the VDH identified three cases of laboratory-confirmed C. jejuni infection in Vermont residents; the
isolates had indistinguishable pulsed-field gel electrophoresis (PFGE)
patterns. PulseNet, the molecular subtyping network for foodborne disease
surveillance, led to one additional case from New Hampshire, New York, and
Vermont reported in the preceding six months.

Farm worker exposed: One of the people was exposed to the
pathogen while working on the farm, the other four cases became ill after eating
the livers, which were deliberately undercooked to maintain their texture.

USDA-FSIS
found that establishment A, which stopped selling chicken livers, used
antimicrobial cleaners to the livers, these efforts only affect the external
surfaces and because Campylobacter contamination can be internal, the safety of
undercooked chicken livers was not assured.

A food
safety assessment conducted by the US Department of Agriculture's Food Safety
and Inspection Service (USDA-FSIS) found no major violations.

The Food
and Drug Administration (FDA) says that poultry must reach an internal
temperature of 165oF (73.9oC) for at least 15 seconds.

Studies have
shown that 77% of retail chicken livers are contaminated with Campylobacter and
contamination is usually in internal tissues as well as on the surface.

Patients affected: The six patients ranged in age from 19 to 87 years; three were female.
Two were hospitalized, but all six had recovered by the time of their
interviews.

Frozen
chicken livers collected from restaurant A were sent to the VDH laboratory,
minced into 13 25-gram subsamples and enriched as normal for the C. jejuni immunoassay. Two of the 13
subsamples screened gave positive results, but the pathogen could not be recovered
in culture.

It is notable
the increase of Listeria tolerance to various sanitizers.

Controlling
the food-borne pathogen Listeria (L.)
monocytogenes is of great importance from a food safety perspective, and
thus for human health. The consequences of failures in this regard have been
exemplified by recent large listeriosis outbreaks in the USA and Europe. It is
thus particularly notable that tolerance to quaternary ammonium compounds such
as benzalkonium chloride (BC) has been observed in many L. monocytogenes
strains.

However,
the molecular determinants and mechanisms of BC tolerance of L. monocytogenes are still largely unknown. Here we describe
Tn6188, a novel transposon in L. monocytogenes conferring tolerance to BC.
Tn6188 is related to Tn554 from Staphylococcus
(S.) aureus and other Tn554-like transposons such as Tn558, Tn559 and Tn5406
found in various Firmicutes. Tn6188 comprises 5117 bp, is integrated
chromosomally within the radC gene and consists of three transposase genes
(tnpABC) as well as genes encoding a putative transcriptional regulator and QacH,
a small multidrug resistance protein family (SMR) transporter putatively
associated with export of BC that shows high amino acid identity to Smr/QacC
from S. aureus and to EmrE from Escherichia coli. We screened 91 L. monocytogenes strains for the presence
of Tn6188 by PCR and found Tn6188 in 10 of the analyzed strains.

Using
quantitative reverse transcriptase PCR we could show a significant increase in
qacH expression in the presence of BC. QacH deletion mutants were generated in
two L. monocytogenes strains and
growth analysis revealed that ΔqacH strains had lower BC MICs than wild type strains. In conclusion,
our results provide evidence that Tn6188 is responsible for BC tolerance in
various L. monocytogenes strains.